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Butternut Squash, Portobello, and Spinach Casserole with Vegan Sausage

My internet spree yesterday morning began with some work emails, and mysteriously turned into a frenzied search for the perfect Thanksgiving vegan casserole recipe. I found plenty of recipes, but most contained things like black beans, chilis and cornbread, and I was hoping for more traditional holiday flavors. I wanted the casserole to be hearty, but not heavy. It had to be indulgent, but healthy. It needed to feel special enough to be the meal’s centerpiece, and be complimented – not overshadowed – by everything else on the table. I think you’ll agree that this casserole is worthy of the spotlight on Thanksgiving Day. I love the earthy, woodsy combination of vegan sausage, barley, mushrooms, sage, and rosemary countered with the mellow sweetness of butternut squash and fresh spinach. A proper Thanksgiving meal should radiate homey, rustic warmth, and this casserole definitely fits the bill. The best part? It can be made a full day ahead, freeing up precious oven real estate on Thanksgiving and leaving you with lots of extra time to primp, prep, and pour yourself a well-deserved glass of champagne before your guests arrive.

Most of these ingredients can be found at your regular supermarket. If you can’t find miso or nutritional yeast (both essential to lending the casserole a subtle cheesy flavor), or vegan sausage, head to a natural foods store like Whole Foods, which regularly stocks these ingredients.

Butternut Squash, Portobello, and Spinach Casserole with Vegan Sausage

This Recipe is :





  • 1 medium butternut squash (around 2.5 lbs), peeled and diced into 1″ cubes
  • 4 Tablespoons extra virgin olive oil, divided
  • 2 links of vegan Field Roast brand sausage, Smoked Apple Sage flavor
  • 3 leeks, white and pale green parts only, washed and cut into thin half-moon slices
  • 2 large cloves of garlic, minced
  • 1 8 oz package of Cremini mushrooms, thinly sliced
  • 2 cups Portobello mushroom soup
  • 1/2 cup vegetable stock
  • 1 teaspoon white miso
  • 2 Tablespoons nutritional yeast
  • 1/4 cup finely chopped fresh sage
  • 1 Tablespoon finely chopped fresh rosemary
  • 1 9 oz bag of baby spinach
  • Kosher salt and black pepper, to taste
  • 3 cups cooked pearl barley (about 1 cup dry cooked per package directions)
  • 2 Tablespoons fresh parsley, finely chopped


  1. Preheat oven to 375 degrees.
  2. In a large bowl, toss the diced butternut squash with 2 Tablespoons of olive oil and a pinch of kosher salt and a few grinds of black pepper.  Once combined, spread the squash out evenly on a large rimmed baking sheet lined with parchment paper.  Place in oven and bake for approximately 30 minutes, or until fork tender.  Remove from oven and set aside.  Leave oven on, but reduce heat to 350 degrees.
  3. Remove Field Roast sausage links from packaging and place in a food processor.  Pulse until the sausage resembles ground sausage.
  4. In a large nonstick pan, heat 1 Tablespoon of olive oil over medium high heat.  Add sausage  and cook until sausage is browned and slightly crispy.  Remove from pan and place on a paper towel lined plate.  Set aside.
  5. In the same nonstick pan, add an additional 1 Tablespoon of olive oil over medium high heat.  Add the leeks and garlic and cook, stirring frequently, until leeks are tender, about 5-7 minutes.  Add the sliced mushrooms, sage, and rosemary and cook an additional 3-4 minutes.  Add the mushroom soup, vegetable stock, nutritional yeast, and miso.  Stir until miso and nutritional yeast have dissolved into the liquid and everything is combined.  Bring to a boil and then immediately reduce heat to low and simmer for 1-2 minutes.  Add the fresh spinach and stir until spinach is completely wilted into mushroom mixture.  Season to taste with salt and pepper, and remove from heat.
  6. Grease a 9×13″ oven safe casserole dish with nonstick spray.  In the dish, gently combine the cooked butternut squash, browned ground sausage, cooked barley, and mushroom mixture with a rubber spatula.  Once combined, spread the mixture evenly throughout the baking dish.  Place in the oven and cook, uncovered, for 35-40 minutes, or until most of the liquid has evaporated and top is evenly golden brown.  Remove from oven and top with fresh chopped parsley.  Let sit for 10 minutes before serving.


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Lauren Kretzer is a vegan private chef serving clients based in the NY Metro area.  She received her formal culinary education at the Natural Gourmet Institute for Health & Culinary Arts in New York City and trained at Annisa, a Michelin-starred New York City restaurant owned by acclaimed chef Anita Lo.  She blogs at La Dolce Pita.



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5 comments on “Butternut Squash, Portobello, and Spinach Casserole with Vegan Sausage”

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Anne Muensch
2 Years Ago

In the 'Butternut Squash, Portobello, and Spinach Casserole with Vegan Sausage ... can I use Quinoa instead of barley? An answer by email would be much appreciated. Thank You Anne Muensch

Anne Muensch
2 Years Ago

Can I use Quinoa instead of barley?

Suzanne Allen
2 Years Ago

Tonight we had a large casserole (Trader Joe's) that was made like this. Very delicious.

Kitu Gidwani
2 Years Ago


Imogene King
2 Years Ago

EmpressRed Dirkoff Courtenay Noble


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